...on opening the incubator I experienced one of those rare moments of intense emotion which reward the research worker for all his pains: at first glance I saw that the broth culture, which the night before had been very turbid was perfectly clear: all the bacteria had vanished... as for my agar spread it was devoid of all growth and what caused my emotion was that in a flash I understood: what causes my spots was in fact an invisible microbe, a filterable virus, but a virus parasitic on bacteria. Another thought came to me also, If this is true, the same thing will have probably occurred in the sick man. In his intestine, as in my test-tube, the dysentery bacilli will have dissolved away under the action of their parasite. He should now be cured.

In Allan Chase, Magic Shots: A Human and Scientific Account of the Long and Continuing Struggle to Eradicated Infectious Diseases by Vaccination (1982), 249-250. Also in Allan J. Tobin and Jennie Dusheck, Asking About Life (2005), 206.

The Antiseptic Baby and the Prophylactic PupWere playing in the garden when the Bunny gamboled up;They looked upon the Creature with a loathing undisguised;—It wasn't Disinfected and it wasn't Sterilized.

They said it was a Microbe and a Hotbed of Disease;They steamed it in a vapor of a thousand-odd degrees;They froze it in a freezer that was cold as Banished HopeAnd washed it in permanganate with carbolated soap.

In sulphurated hydrogen they steeped its wiggly ears;They trimmed its frisky whiskers with a pair of hard-boiled shears;They donned their rubber mittens and they took it by the handAnd elected it a member of the Fumigated Band.

There's not a Micrococcus in the garden where they play;They bathe in pure iodoform a dozen times a day;And each imbibes his rations from a Hygienic Cup—The Bunny and the Baby and the Prophylactic Pup.

Printed in various magazines and medical journals, for example, The Christian Register (11 Oct 1906), 1148, citing Women's Home Companion. (Making fun of the contemporary national passion for sanitation.)

A bewildering assortment of (mostly microscopic) life-forms has been found thriving in what were once thought to be uninhabitable regions of our planet. These hardy creatures have turned up in deep, hot underground rocks, around scalding volcanic vents at the bottom of the ocean, in the desiccated, super-cold Dry Valleys of Antarctica, in places of high acid, alkaline, and salt content, and below many meters of polar ice. ... Some deep-dwelling, heat-loving microbes, genetic studies suggest, are among the oldest species known, hinting that not only can life thrive indefinitely in what appear to us totally alien environments, it may actually originate in such places.

Poem (1904) answering the question: How old are fleas?. 'On the Antiquity of Microbes', Strickland W. Gillilan. For some years it was considered the shortest poem until 'Lines on the Questionable Importance of the Individual': “I … Why?” appeared from Anon. (As quoted in S.N. Behrman, The New Yorker (27 May 1972), 38-81. In The Lyceum News (1911), 2, No. 1, 15, it is noted that 14-year-old Charles E. Varney, Jr. recited the poem in his English class, but the teacher said the assignment had specified a poem to be complete in at least four lines long. So he continued: “Well’m / I'll add ’em / So had / Madam.”

I can think of a few microorganisms, possibly the tubercle bacillus, the syphilis spirochete, the malarial parasite, and a few others, that have a selective advantage in their ability to infect human beings, but there is nothing to be gained, in an evolutionary sense, by the capacity to cause illness or death. Pathogenicity may be something of a disadvantage for most microbes…

If it is a terrifying thought that life is at the mercy of the multiplication of these minute bodies [microbes], it is a consoling hope that Science will not always remain powerless before such enemies...

It is usually not recognized that for every injurious or parasitic microbe there are dozens of beneficial ones. Without the latter, there would be no bread to eat nor wine to drink, no fertile soils and no potable waters, no clothing and no sanitation. One can visualize no form of higher life without the existence of the microbes. They are the universal scavengers. They keep in constant circulation the chemical elements which are so essential to the continuation of plant and animal life.

Microbiology is usually regarded as having no relevance to the feelings and aspirations of the man of flesh and bone. Yet, never in my professional life do I find myself far removed from the man of flesh and bone. It is not only because microbes are ubiquitous in our environment, and therefore must be studied for the sake of human welfare. More interesting, and far more important in the long run, is the fact that microbes exhibit profound resemblances to man. They resemble him in their physical makeup, in their properties, in their responses to various stimuli; they also display associations with other living things which have perplexing and illuminating analogies with human societies.

Now, it may be stretching an analogy to compare epidemics of cholera—caused by a known agent—with that epidemic of violent crime which is destroying our cities. It is unlikely that our social problems can be traced to a single, clearly defined cause in the sense that a bacterial disease is ‘caused’ by a microbe. But, I daresay, social science is about as advanced in the late twentieth century as bacteriological science was in the mid nineteenth century. Our forerunners knew something about cholera; they sensed that its spread was associated with misdirected sewage, filth, and the influx of alien poor into crowded, urban tenements. And we know something about street crime; nowhere has it been reported that a member of the New York Stock Exchange has robbed ... at the point of a gun. Indeed, I am naively confident that an enlightened social scientist of the next century will be able to point out that we had available to us at least some of the clues to the cause of urban crime.

Populations of bacteria live in the spumes of volcanic thermal vents on the ocean floor, multiplying in water above the boiling point. And far beneath Earth's surface, to a depth of 2 miles (3.2 km) or more, dwell the SLIMES (subsurface lithoautotrophic microbial ecosystems), unique assemblages of bacteria and fungi that occupy pores in the interlocking mineral grains of igneous rock and derive their energy from inorganic chemicals. The SLIMES are independent of the world above, so even if all of it were burned to a cinder, they would carry on and, given enough time, probably evolve new life-forms able to re-enter the world of air and sunlight.

The Microbe is so very small,You cannot make him out at all. But many sanguine people hopeTo see him down a microscope.His jointed tongue that lies beneathA hundred curious rows of teeth; His seven tufted tails with lotsOf lovely pink and purple spotsOn each of which a pattern stands, Composed of forty separate bands; His eyebrows of a tender green;All these have never yet been seenBut Scientists, who ought to know, Assure us they must be so ... Oh! let us never, never doubtWhat nobody is sure about!

These microscopic organisms form an entire world composed of species, families and varieties whose history, which has barely begun to be written, is already fertile in prospects and findings of the highest importance. The names of these organisms are very numerous and will have to be defined and in part discarded. The word microbe which has the advantage of being shorter and carrying a more general meaning, and of having been approved by my illustrious friend, M. Littré, the most competent linguist in France, is one we will adopt.

To demonstrate experimentally that a microscopic organism actually is the cause of a disease and the agent of contagion, I know no other way, in the present state of Science, than to subject the microbe (the new and happy term introduced by M. Sédillot) to the method of cultivation out of the body.

Why then be concerned about the conservation of wildlife when for all practical purposes we would be much better off if humans and their domestic animals and pets were the only living creatures on the face of the earth? There is no obvious and demolishing answer to this rather doubtful logic although in practice the destruction of all wild animals would certainly bring devastating changes to our existence on this planet as we know it today...The trouble is that everything in nature is completely interdependent. Tinker with one part of it and the repercussions ripple out in all directions...Wildlife - and that includes everything from microbes to blue whales and from a fungus to a redwood tree - has been so much part of life on the earth that we are inclined to take its continued existence for granted...Yet the wildlife of the world is disappearing, not because of a malicious and deliberate policy of slaughter and extermination, but simply because of a general and widespread ignorance and neglect.

In 'Champion Among Microbe Hunters', Reader’s Digest (1950), 35–40. As quoted and cited in Mark Honigsbaum, '‘Tipping the Balance’: Karl Friedrich Meyer, Latent Infections,and the Birth of Modern Ideas of Disease Ecology', Journal of the History of Biology (2016), 49, 267.

“Men die of the diseases which they have studied most,” remarked the surgeon, snipping off the end of a cigar with all his professional neatness and finish. “It’s as if the morbid condition was an evil creature which, when it found itself closely hunted, flew at the throat of its pursuer. If you worry the microbes too much they may worry you. I’ve seen cases of it, and not necessarily in microbic diseases either. There was, of course, the well-known instance of Liston and the aneurism; and a dozen others that I could mention.”

In science it often happens that scientists say, 'You know that's a really good argument; my position is mistaken,' and then they would actually change their minds and you never hear that old view from them again. They really do it. It doesn't happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day. I cannot recall the last time something like that happened in politics or religion.
(1987) -- Carl Sagan